PROJECT SUMARY/ABSTRACT New, expensive risk assessment technologies are rapidly being integrated into the care of patients with prostate cancer. Advanced imaging (prostate MRI) and genomic tests have been developed and are now deployed to overcome a central challenge in the management of the disease: a remarkably high prevalence, yet comparatively low lethality. For decades, uncertainty regarding the true nature of a patient's prostate cancer has led to the unnecessary treatment of indolent (`low-risk') disease in millions of men resulting in lasting side-effects for many. By improving the ability to distinguish low-risk from aggressive cancers, it is believed that more accurate tools will allow many patients to safely observe low-risk cancers with careful monitoring (active surveillance). Although these two ascendant technologies have been evaluated in controlled studies, no real-world evidence is available to understand their impact. Specifically, it is not known which patients are receiving testing, whether use of these technologies reduces unnecessary treatment, or how patients and doctors perceive of their benefit. To address these knowledge gaps, we aim to comprehensively understand how prostate MRI and genomic testing impact the management of prostate cancer. We will accomplish this goal through two complementary phases aimed at: (1) defining how adoption of prostate MRI and/or genomic testing has affected clinical management, and (2) understanding how patients and physicians perceive of these tools during decision-making. We hypothesize that whether or not prostate MRI and/or genomic testing are performed is dependent on the doctor that they see, but that testing is associated with lower rates of treatment. We will use large national datasets of men with prostate cancer and examine the adoption of prostate MRI and/or genomic testing, and whether the use of these technologies is associated with increased use of observation versus treatment. To learn how these tools are used in decision-making for low- risk prostate cancer, we will conduct in-depth interviews of both patients with prostate cancer and doctors who diagnose and treat the disease. The results from this research will shape efforts to improve how these tools are used in the management of men with prostate cancer. Candidate: this proposal supports the professional development of the candidate as an independent, patient-oriented surgeon-investigator focusing on improving prostate cancer care. This application is centered around a rigorous training program including coursework that leverages the candidate's background as a prostate cancer surgeon and clinical outcomes researcher whose prior work has focused on risk assessment technologies and active surveillance of low-risk prostate cancer. The applicant will build upon his expertise by earning a Masters in Health Science from Yale University, and develop a skill set in qualitative research and implementation science. The completion of this mentored training award will position the candidate to develop and test a framework for refining the use of new technologies for patients with prostate cancer, potentially reducing over-treatment and cost.